Normal brain fetal MRI - 22 weeks

Case contributed by Stacy Goergen
Diagnosis certain


Suspected abnormality on ultrasound, referred for fetal MRI.

Patient Data

Age: 22w4d GA
Gender: Female

Normal fetal brain at 22 weeks gestation (unlabelled - see labeled images below).  Note the five layered laminar appearance, appropriate for this stage of gestation. The Sylvian fissures are becoming squared, but still open. The parieto-occipital fissures are present, and the calcarine fissures are becoming visible. The cingulate sulcus is not yet visible. The brain surface is generally smooth, with no secondary or tertiary sulci present.

Annotated image

Key features of cerebral lamination and sulcation at 22 weeks gestation.

The Sylvian fissure is deeper and more squared, but temporal lobes have not yet begun to cover the operculum. Calcarine, parieto-occipital and hippocampal fissures are nor visible.

Normal lamination. Note the normal five-layered laminar pattern with alternating T2 dark and bright bands, seen in fetuses from 20 to 30 weeks gestation. From inner to outer, the layers are:

1. ventricular zone (arrowhead)

2. periventricular fiber-rich zone (dotted arrow)

3. intermediate zone (curved arrow)

4. sub-plate (long thin arrow)

5. cortex (short thick arrow)

Note the normal appearance of ganglionic eminences.

Case Discussion

Normal fetal brain MRI at 22 weeks gestation, demonstrating the key cerebral features seen at this stage.

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